Dual-functional electrochemical bio-sensor built from Cu2O for sensitively detecting the thiols and Hg2+

Abstract

Electrochemical bioanalysis has been drawing more attention in recent years, due to the advantages of fast and effective detection capabilities. Intracellular thiols including biothiols (glutathione (GSH), cysteine (Cys) and homocysteine (Hcy)) and endogenous H2S play important biological roles in physiological processes. Therefore, the development of a method for detecting biothiols and distinguishing from endogenous H2S has become a challenge to be addressed. In this work, Cu2O nanostructure was successfully synthesized by electrodeposition process and employed as core part of electrochemical sensing platform for sensitive detecting thiols. The sensor exhibits excellent sensing performance, which is due to the interaction of -SH with Cu (I) via the formation of Cu-S bond. Significantly, the sensor establishes a novel approach for distinguishing biothiols and S2- via different peak current responses for the first time. The limit of detections of the sensor for Cys and S2- have achieved to 6.2 nM and 11.3 nM, respectively. The practical applicability of the sensor was assessed in human urine samples. It is noteworthy that Cu2O-S and Cu2O-Cys systems have been found significant response toward Hg2+, which can be used for detecting Hg2+. The detection limit of Cu2O-S system for Hg2+ was realized at 0.3 nM.